[cleanup] [broker] when serverCnx.disabledAutoRead(), use same code (a…

…pache#15181)

Co-authored-by: fengyubiao <[email protected]>

pulsar-broker/src/main/java/org/apache/pulsar/broker/service/ServerCnx.java

@@ -2647,8 +2647,7 @@ public void startSendOperation(Producer producer, int msgSize, int numMessages)
         if (++pendingSendRequest == maxPendingSendRequests || isPublishRateExceeded) {
             // When the quota of pending send requests is reached, stop reading from socket to cause backpressure on
             // client connection, possibly shared between multiple producers
-            ctx.channel().config().setAutoRead(false);
-            recordRateLimitMetrics(producers);
+            disableCnxAutoRead();
             autoReadDisabledRateLimiting = isPublishRateExceeded;
             throttledConnections.inc();
         }